Hepatic Stellate Cells and Liver Fibrosis

2007 ◽  
Vol 131 (11) ◽  
pp. 1728-1734 ◽  
Author(s):  
Roger Klein Moreira
Keyword(s):  
Growth Factor ◽  
Liver Fibrosis ◽  
Hepatic Stellate Cells ◽  
Transforming Growth Factor ◽  
Stellate Cells ◽  
Transforming Growth Factor Β ◽  
Platelet Derived Growth Factor ◽  
Activation Process ◽  
Substantial Evidence ◽  
Rate Of Progression

Abstract Substantial evidence now exists to recognize hepatic stellate cells (HSCs) as the main matrix-producing cells in the process of liver fibrosis. Liver injury of any etiology will ultimately lead to activation of HSCs, which undergo transdifferentiation to fibrogenic myofibroblast-like cells. Quantitative analysis of HSC activation by immunohistochemistry has been shown to be useful in predicting the rate of progression of liver fibrosis in some clinical situations. In the activation process, transforming growth factor β is thought to be the main mediator of fibrogenesis and platelet-derived growth factor is the major inducer of HSC proliferation. Different platelet-derived growth factor and transforming growth factor β inhibitors have been shown to effectively prevent liver fibrosis in animal models and represent promising therapeutic agents for humans.

Cellular crosstalk mediated by platelet-derived growth factor BB and transforming growth factor β during hepatic injury activates hepatic stellate cells

2018 ◽  
Vol 96 (8) ◽  
pp. 728-741 ◽  
Author(s):  
Sowmya Mekala ◽  
SubbaRao V. Tulimilli ◽  
Ramasatyaveni Geesala ◽  
Kanakaraju Manupati ◽  
Neha R. Dhoke ◽  
...  
Keyword(s):  
Growth Factor ◽  
Hepatic Stellate Cells ◽  
Hepg2 Cells ◽  
Molecular Mechanisms ◽  
Transforming Growth Factor ◽  
Stellate Cells ◽  
Transforming Growth Factor Β ◽  
Platelet Derived Growth Factor ◽  
Hepatic Tissue

Apoptotic hepatocytes release factors that activate hepatic stellate cells (HSCs), thereby inducing hepatic fibrosis. In the present study, in vivo and in vitro injury models were established using acetaminophen, ethanol, carbon tetrachloride, or thioacetamide. Histology of hepatotoxicant-induced diseased hepatic tissue correlated with differential expression of fibrosis-related genes. A marked increase in co-staining of transforming growth factor β receptor type II (TGFRIIβ) – desmin or α-smooth muscle actin – platelet-derived growth factor receptor β (PDGFRβ), markers of activated HSCs, in liver sections of these hepatotoxicant-treated mice also depicted an increase in Annexin V – cytokeratin expressing hepatocytes. To understand the molecular mechanisms of disease pathology, in vitro experiments were designed using the conditioned medium (CM) of hepatotoxicant-treated HepG2 cells supplemented to HSCs. A significant increase in HSC proliferation, migration, and expression of fibrosis-related genes and protein was observed, thereby suggesting the characteristics of an activated phenotype. Treating HepG2 cells with hepatotoxicants resulted in a significant increase in mRNA expression of platelet-derived growth factor BB (PDGF-BB) and transforming growth factor β (TGFβ). CM supplemented to HSCs resulted in increased phosphorylation of PDGFRβ and TGFRIIβ along with its downstream effectors, extracellular signal-related kinase 1/2 and focal adhesion kinase. Neutralizing antibodies against PDGF-BB and TGFβ effectively perturbed the hepatotoxicant-treated HepG2 cell CM-induced activation of HSCs. This study suggests PDGF-BB and TGFβ as potential molecular targets for developing anti-fibrotic therapeutics.

scholarly journals Integrin αVβ1 Regulates Procollagen I Production through a Non-canonical Transforming Growth Factor β Signaling Pathway in Human Hepatic Stellate Cells

2021 ◽  
Author(s):  
Zuoning Han ◽  
Yanling Ma ◽  
Gary Cao ◽  
Zhengping Ma ◽  
Ruihua Chen ◽  
...  
Keyword(s):  
Growth Factor ◽  
Liver Fibrosis ◽  
Hepatic Stellate Cells ◽  
Transforming Growth Factor ◽  
Specific Inhibitor ◽  
Stellate Cells ◽  
Transforming Growth Factor Β ◽  
Current Data ◽  
Human Hscs ◽  
Tgf Β1

Hepatic stellate cells (HSCs) are thought to play key roles in the development of liver fibrosis.  Extensive evidence has established the concept that αV integrins are involved in the activation of latent transforming growth factor β (TGF-β), a master regulator of the fibrotic signaling cascade.  Based on mRNA and protein expression profiling data, we found that αVβ1 integrin is the most abundant member of the αV integrin family in either quiescent or TGF-β1-activated primary human HSCs.  Unexpectedly, either a selective αVβ1 inhibitor, Compound 8 (C8), or a pan-αV integrin inhibitor, GSK3008348, decreased TGF-β1-activated procollagen I production in primary human HSCs, in which the role of β1 integrin was confirmed by ITGB1 siRNA. In contrast to an Activin receptor-like kinase 5 (Alk5) inhibitor, C8 and GSK3008348 failed to inhibit TGF-β1 induced SMAD3 and SMAD2 phosphorylation, but inhibited TGF-β-induced phosphorylation of ERK1/2 and STAT3, suggesting that αVβ1 integrin is involved in non-canonical TGF-β signaling pathways. Consistently, ITGB1 siRNA significantly decreased phosphorylation of ERK1/2. Furthermore, a selective inhibitor of MEK1/2 blocked TGF-β1 induced phosphorylation of ERK1/2 and decreased TGF-β1 induced procollagen I production, while a specific inhibitor of STAT3 had no effect on TGF-β1 induced procollagen I production.  Taken together, current data indicate that αVβ1 integrin can regulate TGF-β signaling independent of its reported role in activating latent TGF-β.  Our data further support that αVβ1 inhibition is a promising therapeutic target for the treatment of liver fibrosis.

Latency-associated Peptide Degradation Fragments Produced in Stellate Cells and Phagocytosed by Macrophages in Bile Duct-ligated Mouse Liver

2021 ◽  
pp. 002215542110536
Author(s):  
Ikuyo Inoue ◽  
Xian-Yang Qin ◽  
Takahiro Masaki ◽  
Yoshihiro Mezaki ◽  
Tomokazu Matsuura ◽  
...  
Keyword(s):  
Bile Duct ◽  
Liver Fibrosis ◽  
Hepatic Stellate Cells ◽  
Mouse Liver ◽  
Transforming Growth Factor ◽  
Degradation Products ◽  
Stellate Cells ◽  
Transforming Growth Factor Β ◽  
Early Stages ◽  
Cell Source

Transforming growth factor-β (TGF-β) activation is involved in various pathogeneses, such as fibrosis and malignancy. We previously showed that TGF-β was activated by serine protease plasma kallikrein-dependent digestion of latency-associated peptides (LAPs) and developed a method to detect LAP degradation products (LAP-DPs) in the liver and blood using specific monoclonal antibodies. Clinical studies have revealed that blood LAP-DPs are formed in the early stages of liver fibrosis. This study aimed to identify the cell source of LAP-DP formation during liver fibrosis. The N-terminals of LAP-DPs ending at residue Arg58 (R58) were stained in liver sections of a bile duct-ligated liver fibrosis model at 3 and 13 days. R58 LAP-DPs were detected in quiescent hepatic stellate cells at day 3 and in macrophages on day 13 after ligation of the bile duct. We then performed a detailed analysis of the axial localization of R58 signals in a single macrophage, visualized the cell membrane with the anti-CLEC4F antibody, and found R58 LAP-DPs surrounded by the membrane in phagocytosed debris that appeared to be dead cells. These findings suggest that in the early stages of liver fibrosis, TGF-β is activated on the membrane of stellate cells, and then the cells are phagocytosed after cell death: (J Histochem Cytochem XX:XXX–XXX, XXXX)

scholarly journals Smads 2 and 3 Are Differentially Activated by Transforming Growth Factor-β (TGF-β) in Quiescent and Activated Hepatic Stellate Cells

2003 ◽  
Vol 278 (13) ◽  
pp. 11721-11728 ◽  
Author(s):  
Chenghai Liu ◽  
Marianna D. A. Gaça ◽  
E. Scott Swenson ◽  
Vincent F. Vellucci ◽  
Michael Reiss ◽  
...  
Keyword(s):  
Growth Factor ◽  
Hepatic Stellate Cells ◽  
Transforming Growth Factor ◽  
Stellate Cells ◽  
Transforming Growth Factor Β ◽  
Activated Hepatic Stellate Cells
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